Gorbachev shakes hands with the Gipper on an October 1986 trip to the White House. Photo: AP

There he goes again, rattling more sabers. Speaking on ABC’s “This Week,” President Obama declared that just because he hasn’t taken action against Syria is no reason for those in Tehran “to think we won’t strike Iran.”

Indeed, the president claims he would be even tougher on Iran, because “the nuclear issue is a far larger issue for us than the chemical-weapons issue.”

By now everyone should recognize this as part of the familiar Obama pattern: Put off what needs to be done today by promising tough action in the future.

As a presidential candidate in 2008, Obama spoke about the need to win the “necessary war” in Afghanistan, which allowed him to wash his hands of Iraq. When he drew his red line on Syria’s use of chemical weapons, it was a way of not having to make good on his insistence that Bashar al-Assad had to go.

And now we’re seeing it again as Obama threatens a strike on Iran tomorrow to distract attention from his pathetic response to Syria today.

The way to convey to a large and dangerous power that you mean business is to act more decisively against smaller proxies. Look at how Ronald Reagan persuaded the USSR he was serious: firing air-traffic controllers, invading Grenada, supplying the Afghan rebels with stingers and shooting down those jets in Libya.

So when the Gipper met with Mikhail Gorbachev, the Russian knew he was sitting across from a man whose actions proved his words meant something. We doubt Vladimir Putin has the same worry about President Obama.

As for those hard men in Iran, they have no reason to fear they will pay any price for their nuclear program — unless it comes from Israel and Bibi Netanyahu.